DIRECT ISOLATION OF OLEFINIC AND ACETYLENIC 3-ALKYL-4-HYDROXY-BUTENOLIDES OCCURRING WITHIN THE APIACEAE

Underivatized alkylbutenolides from several Peucedanum species includi ng P. alsaticum L., P. austriacum (Jacq.) Koch, P. arenarium Waldst. a nd Kit., P. venetum (Sprengel) Koch and P. rablense (Wulfen) Koch (Api aceae-Apioideae) were separated by high performance liquid chromatogra phy and preparative chromatography on a reversed phase system at a pH of 2.5. The chromatographic separation on RP-18 with methanol:water as eluent is strongly affected by the enol-enolate equilibrium of these compounds. In protic solutions these compounds exist as enolate anions . The dissociation constant of alkylbutenolides in methanol:water mixt ures was determined. The alkylbutenolides show rather good solubility in polar solvents and high acidity compared to the corresponding fatty acids.